1. Field of the Invention
This invention relates to an improved apparatus for measuring the test weight per bushel of grain and doing the same automatically.
2. Prior Art
The test weight per bushel for grain is an important factor in assigning a grade to a lot of grain under the official grain standards of the United States. It is therefore essential that the test weight per bushel be accurately measured as it affects the market value of the grain.
The known test weight per bushel tester designed by the U.S. Department of Agriculture is described in USDA Circular 921 of June 1953 which supersedes Bulletin 1065 issued May 1922. This standard weight per bushel testing apparatus consists of a stand, a filling hopper, a test kettle, a weighing beam, an overflow pan and a stroker as shown in FIG. 2 of USDA Circular 921. The standard weight-per-bushel tester is so designed that when the test kettle is properly filled and the surplus grain is struck off, it contains exactly one dry quart or 67.2 cubic inches of grain. When the filled test kettle is weighed the weight of the contents may be determined directly in pounds per bushel as there are 32 quarts to the bushel and the weighing beam indicates 32 times the actual contents of the test kettle.
The standard method of determining weight per bushel includes a series of steps which require some skill and faithful compliance. See page 4 of USDA Circular 921. This Circular also lists 10 variations or factors which will cause errors in the test weight per bushel even using the standard approved apparatus, see pages 4, 5.
Additionally, in addition to requiring at least semi-skilled operators, the USDA approved test is time consuming of personnel. However, the USDA method is accurate, is officially and governmentally accepted, and is almost universally used in the United States. Nonetheless there is a need to automate the method, to eliminate the need for semi-skilled or skilled workers and to speed up the measurement while eliminating the factors which can cause errors in test weight measurements.